It was only this weekend that I was first introduced to Decimal Defender, an educational math game published by TI Education for the TI-83 Plus/TI-84 Plus calculators (available for download on their site). You control a spaceship, numbers appear at the top, and a math problem involving multiplying or dividing a number by a power of 10 appears at the bottom. You need to shoot the spot where the decimal point should go. Each wrong answer loses you a life. I figured it would be a fun little xLIBC program to write, and educational to boot, so I have a tentative spritesheet and have started writing the game. I'll update this topic as I make progress.

Edit: Many improvements, including display of the problem you're working on and detection of right/wrong/loss conditions. Some problems are unsolveable because there's not enough space at the left. Multiplication problems are not recognized as correct.

On the unsolvable, any chance of shoving the numbers to the right to give the 0's priority? Looks fantastic, though What kind of points system does it use?

The readme for the original says the following for the points (which I have not implemented yet):

Quote:

You accumulate points for your combination of speed and
accuracy, as well as the difficulty of the operation. More points
are awarded when the operation is BOTH than when it is
MULTIPLICATION or DIVISION.

Yes, I plan to fix the unsolveable bug that way, even though it should already be doing that. I have been collecting a list of problems posed that created this issue. I added a main menu and a demo mode, and I also implemented a somewhat unorthodox hack of a half-sized xLIBC spritesheet.

Remaining issues/features:
- Numbers of the form 0.00ABCD aren't displayed correctly in question
- Stars, including drawing during number rendering and during ship movement?
- Fix left side of ship sprite on dark backgrounds
- Beta-testing! Any volunteers?
- Questions or comments?

I'm sorry if this question doesn't belong here, but just wondering how you do the small text... I can't do anything but the large blocky text.
And great work! I don't think I've played the original on the 84+ but looks good. I really like the ship sprite. Nicely done as always Kerm.

Most of the text looks like it's just from xLIB. The numbers at the top are probably just sprites that he's drawing. I don't see any "small text".

Looks really good, Kerm. Great work

Thanks! As Merth says, most of the text is the standard xLIBC font. The exception is the big numbers at the top, which are a set of 10 digits in my spritesheet.

tifreak8x wrote:

Quite the list of features! Looks awesome, can't wait to play it.

I may make you eat those words with some brief beta-testing today if you have the time for it.

Edit:
- Numbers of the form 0.00ABCD aren't displayed correctly in question Done
- Stars, including drawing during number rendering and during ship movement? Done
- Fix left side of ship sprite on dark backgrounds Skipped

Looks very nice and fun to play. Also yeah I was wondering about those small fonts. I was sure at first that you just drew one column of pixel at a time, but skipping one and so on, or something like that.

Nice work and it really does demonstrate the rapid prototyping->dev that you can do with DCS8.0 + SC.

I think you mean xLIBC + DCSE8.0 + SC Much of this insanity would be entirely impossible without xLIBC, even though I'm very much abusing the two buffers in a way I don't think you intended. I'm happy with how it turned out, and I'm looking around to see if TI has any other monochrome edutaining games or purely educational programs I can port to more DCSE programs.

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